Hereditary breast and ovarian cancer (HBOC) syndrome and Lynch syndrome increase individual risk for breast, ovarian, colorectal (CRC), and uterine cancers.¹ Inherited mutations associated with these syndromes account for up to 10% of each of these cancers in the United States.¹ In addition to these genetic syndromes, family medical history (FMH) is an established risk factor for blood relatives to develop the same or related cancers. Along with shared genetic risk factors, families may also share the same environment and exposures, and similar health behaviors which lead to increased cancer risk.

Nearly 8% of people in the United States report having a first-degree relative with a history of breast cancer; 7.1%, with a history of lung cancer; 5.0%, with a history of CRC; 4.7%, with a history of prostate cancer; and 1.8%, with a history of ovarian cancer.² Having a first-degree relative with breast cancer increases an individual’s risk two-fold.³ Similarly, having a first-degree relative diagnosed with CRC doubles a person’s risk.⁴ Convincing evidence demonstrates that alcohol consumption increases risk for both pre- and postmenopausal breast cancers⁵ and CRC.⁶ Obesity increases risk for endometrial,⁷ CRC,⁶ and postmenopausal breast cancer.⁵ Regular physical activity is associated with a lower risk of colon cancer,⁸ and likely reduces risk for endometrial cancer⁷ and breast cancer in postmenopausal women.⁵ Tobacco use can increase risk for CRC,⁹ and may modestly increase breast cancer risk based on findings from recent large prospective cohort studies.¹⁰ Fruit and vegetable consumption ^5,11 and dietary intake of fat⁵ likely have little effect on breast cancer risk. Although fruit and vegetable consumption has not been consistently linked with CRC,¹¹ consumption of red and processed meat may increase risk, while high fiber diets may lower risk.⁶ Approximately 23% of CRC cases could be prevented through the combination of no smoking, regular physical activity, limiting alcohol use, and maintaining a healthy diet and waist circumference. ¹²

Modification of dietary and lifestyle behaviors can reduce the risk of breast and CRC even in individuals with FMH of these cancers.^13,14 While cancer screening test use is higher in persons with FMH of CRC^15,16 and breast cancer¹⁶; less is known about their health behaviors at the population-level.¹⁷ Additionally, few studies have addressed how FMH can be used to motivate individuals to adopt and maintain healthy lifestyles to reduce disease risk.¹⁸

The aim of this study is to examine health behaviors (maintenance of healthy weight, prudent alcohol use, regular physical activity, fruit and vegetable consumption, and no smoking) of Californians who report having one or more family members with a history of cancer (primarily in first-degree relatives), compared with health behaviors of individuals who report no FMH of cancer in a first-degree relative, with emphasis on family history of breast or ovarian cancers, CRCs, and FMH of early onset cancer in a first-degree relative. CRC and breast cancer screening test use is also compared among these individuals. We utilized the 2005 California Health Interview Survey (CHIS), a population-based survey to examine these factors.

Prevalence of FMH of cancer was higher among women, older age groups, and more educated, higher income individuals (Table 2). Non-Latino whites and American Indians/Alaska Natives (42.8% and 37.5%, respectively) reported a higher prevalence of any FMH of cancer, while Asian/Pacific Islanders and Latinos had the lowest prevalence (22.1%, and 17.6%, respectively; P < 0.0001). Prevalence of FMH of cancer was more often reported by individuals with health care coverage and who had a usual health care provider.

Nearly 45% of men and women with FMH of CRC consumed five or more servings of fruits and vegetables per day compared to 49.5% of men and women without FMH of cancer (Table 3; P =0.0057). After adjustment for demographic characteristics and health care access, men and women with FMH of CRC were 16% less likely to consume five or more servings of fruits and vegetables per day (OR=0.84, 95% CI [0.73, 0.96]). After adjustment for demographic characteristics and health care access in multivariate models, no significant differences were found for binge drinking. Men and women with FMH of any cancer had lower rates of a BMI < 25.0 kg/m² compared to men and women with no FMH of cancer (42.6% vs. 45.7%, respectively; P =0.0001); results are similar for persons with FMH of CRC (39.4%, P =0.0011) and FMH of early onset cancer (41.6%, P =0.0074). After adjustment for demographic characteristics and health care access, men and women with FMH of any cancer were 9% less likely to report being normal/underweight compared to persons without FMH of cancer (OR=0.91, 95% CI [0.85, 0.98]), and men and women with FMH of CRC were 20% less likely to report being normal/underweight (OR=0.80; 95% CI [0.67, 0.94]).

Among men and women aged ≥ 50 years with FMH of CRC, 71.5% were up-to-date with CRC screening, compared to 44.5% of persons without FMH of cancer (P <0.0001). After adjustment for demographic characteristics and health care access, men and women with FMH of CRC were nearly 2.8 times more likely to be up-to-date (OR=2.77; 95% CI [2.20, 3.49]); while persons with FMH of any cancer and persons with FMH of early onset cancer were more likely to be up-to-date compared to persons without FMH of cancer (OR=1.33, 95% CI [1.17, 1.51] and OR=1.37, 95% CI [1.12, 1.66], respectively). Nearly 58% of men and women aged 40 – 64 years with FMH of CRC and 53% with FMH of early onset CRC were up-to-date at screening intervals recommended for the average-risk population (P <0.0001 and P <0.0001, respectively). Among this age group, 42.0% of persons with FMH of early onset CRC had received a colonoscopy within the past five years (P <0.0001). These findings were nearly identical to all persons with FMH of CRC.

Although women with FMH of breast or ovarian cancer reported higher levels of regular physical activity, lower rates of not being a current smoker, and lower rates of normal/underweight status compared to women without FMH of cancer, these differences for physical activity, smoking status, and weight disappeared after adjustment for demographic characteristics and health care access (Table 4).

Eighty-five percent of women aged 40 – 64 years with FMH of breast or ovarian cancer had received a mammogram within the past two years, compared to 73.7% of women without FMH of cancer (P <0.0001). After adjustment for demographic characteristics and health care access, women with FMH of breast or ovarian cancer were nearly 1.7 times more likely to be up-to-date compared to women without FMH of cancer (OR=1.69, 95% CI [1.39, 2.04]). Among women aged 30 – 64 years who had received a mammogram within the past two years, 33.2% of women with FMH of breast or ovarian cancer and 41.7% with FMH of early onset breast or ovarian cancer reported that the reason for the test was due to family history, compared to 2.6% of women with no FMH of any cancer (P <0.0001). Younger women (aged 30 – 49 years) more frequently reported family history as a reason for the test than older women (data not shown). Fifty-six percent of women aged 30 – 64 years with FMH of early onset breast or ovarian had received a mammogram within the past year (P <0.0001). Rates were highest among women aged 50 – 59 years (78.7%) compared to women aged 30 – 39 years and 40 – 49 years (28.4% and 55.5%, respectively; data not shown).

In this large, population-based study, we found that men and women with an FMH of CRC were less likely to maintain a healthy weight and consume 5 or more servings of fruits and vegetables per day (which increases risk for CRC), than those without FMH of cancer. Conversely, we found that men and women with FMH were more likely to be up-to-date with cancer screenings than those without. To our knowledge, these weight-related findings are some of the first to be presented for individuals with cancer FMH. Additionally, our study, being one of only a few that is population-based, strengthens the literature on all health behaviors and cancer screenings in those with FMH of cancer.

While our findings on healthy weight among individuals with FMH of CRC appear to be novel, our health behavior findings on physical activity and alcohol use are generally similar to those from other recent studies. ^17,23 In our study, women with FMH of breast or ovarian cancer had health behaviors similar to women without FMH of cancer. Other studies have found similar results,^24,25 although some studies have found more intense or higher levels of physical activity in women with a family history of breast cancer,^26–28 or greater practice of health behaviors was observed, compared with the general population.²⁶ In some of these studies, data were drawn on women of higher education or socioeconomic status;^26,28 therefore, these findings may not be generalizable to other populations, including ours.

Taken together, our health behavior findings indicate that there may be missed opportunities to improve the health of a population that is at increased risk of cancer. FMH of cancer represents a complex interaction between genes and environment. Since only a small fraction of cancer cases are attributable to hereditary syndromes, clinicians should consider health behavior counseling when they encounter patients with FMH of cancer, because they may be exhibiting the same negative behaviors that likely contributed to their relative’s cancer. Studies have shown that persons with FMH of breast or CRC are more likely to receive recommendations from health care providers to improve health behaviors, but the overall number receiving these recommendations may be low.^17,29 In one study, women with FMH of breast cancer were more likely to report making one or more health behavior changes because of a recently diagnosed first-degree relative.³⁰ Persons with a FMH of CRC may also be willing to make health behavior changes and to follow through,¹⁷ but awareness of risk factors for CRC may be low.³¹ Additionally, awareness of FMH of cancer may not always translate into positive health behaviors. Conversely, it may place too much emphasis on genetic susceptibility.³² In this study, we were unable to assess if our study findings were due to a lack of awareness of risk factors for breast and CRC. Regardless, patients with an FMH of cancer may benefit from a targeted approach to improving their health behaviors. Findings from the Family Healthware Impact trial indicate modest increases in physical activity levels after a targeted intervention.³³

Results from our cancer screening analysis showed that women with FMH of breast or ovarian cancer were nearly 1.7 times more likely to be up-to-date with mammography screening compared to women without FMH of cancer, but nearly 15% were not up-to-date with recommendations for women at average risk for breast cancer. Although men and women with FMH of CRC were 2.8 times more likely to be recently screened compared to men and women without FMH of cancer, nearly 29% were not currently up-to-date with recommendations for average-risk individuals. Nearly 42% of women with FMH of early onset breast or ovarian cancer reported that the reason for their last mammogram was due to FMH of cancer. Although sample sizes were small, we found this varied considerably by age. Younger women more frequently reported family history as a reason compared to older women. Our findings of increased cancer screening test use among Californians with FMH of cancer are similar to other studies that examine this. ^15,16 These findings indicate that many patients and their health care providers recognize the increased risk conferred by FMH of cancer. However, screening for CRC is suboptimal for men and women with FMH of early onset CRC; 58% had not received a colonoscopy within the past 5 years. While having a FMH of cancer did increase the odds of breast and CRC screening, a considerable portion of individuals in our study with FMH of early onset CRC, breast or ovarian cancer were not appropriately screened considering their FMH profile. Although sample sizes were small, only 28% of women aged 30 – 39 years with a FMH of early onset breast or ovarian cancer had received a mammogram within the past year (data not shown).These study findings may be due in part to the challenges of collecting FMH of cancer in the clinical setting. Primary care clinicians are often the first healthcare providers to ascertain family health histories and refer patients for cancer screening.³⁴ Barriers to collecting the FMH include lack of time,^18,34 limited tools for use in primary care,³⁴ concerns about validity of self-reported FMH,³⁵ and lack of clear guidelines to assist in collecting, interpreting, and using FMH for disease risk management.³⁶ Some investigators have indicated that the accuracy of self-reports of FMH of cancer may be improved if tools rather than interviews are used,³⁴ and if information is collected outside of clinical visits, where it could be checked with relatives.³⁵ The US Surgeon General’s family health history initiative encourages Americans to learn more about their family’s health history, and a computerized tool is available to record family health information (available at http://www.hhs.gov/familyhistory/). Guidelines on how to systematically assess risk of cancer or use the information to guide prevention efforts is limited, but some resources are available to providers. The American Medical Association provides resources and tools to assist providers in collecting histories (available at http://www.ama-assn.org/ama/pub/physician-resources/medical-science/genetics-molecular-medicine/family-history.page?). As electronic medical records (EMRs) are increasingly adopted by primary care physicians, existing tools must be able to interface or be integrated into these systems. However, EMRs may allow more extensive FMHs to be assembled more easily.³⁷

This study is subject to some limitations. Currently, standardized definitions do not exist for moderate and high risk FMH of cancer profiles, so some respondents may have been misclassified. CHIS is a cross-sectional telephone survey, so self-reported demographic, health behavior, FMH, and cancer screening information may all be subject to social desirability bias. FMH of cancer was not verified against medical records or cancer registry data, so under- or over-reporting was possible, and this likely occurred with endometrial cancer, which is not reported as accurately as other cancer sites.³⁸ Foreign-born status may partially explain racial and ethnic differences in reporting FMH of cancer.³⁹ However, accurate self-reporting of family history of cancer in first-degree relatives for breast, CRC, and prostate cancer is high.³⁸ Our results for California are not generalizable to the overall United States population. Because we examined seven different outcomes for several different cancer FMH profiles, some findings may be due to chance alone. Despite these limitations, few population-based surveys collect data on FMH of cancer that includes age of onset and second-degree relatives. CHIS is a large health survey from a racially and ethnically diverse population, therefore most of our analyses were not constrained by small sample sizes.